The present invention relates generally to electric field sensors, and more particularly to sensors capable of detecting the electromagnetic pulse that accompanies a nuclear explosion.
A precursor to the blast radiation, heat and subsequent radioactive fallout of a nuclear detonation is an electromagnetic pulse (EMP). Various prior art nuclear detonation sensor systems include the use of radiation sensors and seismic sensors (which detect radiation and blast effects) as well as electromagnetic sensors responsive to EMP. Exemplary in the art are the systems of the following U.S. Patents, the disclosures of which are incorporated herein by reference:
U.S. Pat. No. 4,219,804 issued to Weischedel;
U.S. Pat. No. 4,277,745 issued to Deno;
U.S. Pat. No. 4,418,314 issued to Nieto, Jr.;
U.S. Pat. No. 4,588,993 issued to Babij et al; and
U.S. Pat. No. 4,595,876 issued to Kuhara et al.
Weischedel discloses an electronic sensor having circuits for identifying electromagnetic radiation signals caused by nuclear detonations. A part of the patented sensor is formed by a rise time discriminator for the incoming signal.
Babij et al discuss a probe system for measuring the E- and H- field intensities of near-field electromagnetic radiation. By keeping the components electrically small the electromagnetic fields are not perturbed.
Nieto, Jr. shows a fast rise time, high voltage, high impedance voltage probe which allows the measurement of picosecond pulses. The probe of this patent utilizes a parallel R-C divider.
In Deno a low frequency electric field exposure monitor integrates personal exposure to an electric field into intervals Of electric field intensity. A broadband electric field sensor is shown in Kuhara et al.
Electric field sensors are useful for EMP monitoring in a nuclear environment for both ground based systems and for aircraft. These electric field sensors actually respond to the time derivative of the electromagnetic pulse, and may be categorized as differential type sensors. In practice, the use of a differential type sensor limits the overall sensor/scope bandpass to half of what it would be if a nondifferentiating sensor was used.
In view of the foregoing discussion, it is apparent that there currently exists the need for a self-integrating electric field sensor, which responds directly to the high power electric field of an EMP environment. The present invention is intended to satisfy that need.